In recent years one of the most popular implantable procedures was a gel-filled silicon bag. This prosthesis has been employed for a number of years for breat augmentation and reconstruction. In U.S. Pat. No. 3,293,663 to Cronin, the breast prosthesis comprises (1) a flexible container approximating the shape of the human breast, (2) a soft gel filling said container, and (3) a layer of porous material attached to one side of said container so that the tissue can grow into said porous material to anchor the prosthesis to the chest wall.
U.S. Pat. Nos. 4,205,401 to Frisch and 4,264,990 to Hamas reveals that when a Cronin-type of prosthesis is implanted after a certain period of time the prosthesis is surrounded by a natural capsule composed of fibrous scar tissue. Although this is a normal tissue reaction to the presence of a foreign body, it has the disadvantage in that the scar may undergo contraction during the healing process. This effect, which is known as the sperical contracture of the prosthesis, leads to a relatively rigid and tense structure. More specifically, as the tissue around the implant contracts the fixed volume of the silicon gel and material within the flexible container is forced into a shape having the smallest possible surface area, i.e. a sphere surrounded by essentially scar tissue. As pointed as by Frisch, the resulting hard spherical prosthesis results in an aesthically undesirable breast.
Both the Frisch and Hamas disclose various prior art efforts to overcome the sperical capsular contracture problem. Disadvantages of the prior art suggestions are also discussed by the patentees. Frisch's invention is to resist capsular contracture by employing a flexible container which has structural restraining means positioned within the container or the container walls which function to restrain the scar tissue pressure. On the other hand, Hamas proposes the use of a special flexible backing of an inert polymeric material which defines passageways and/or compartments into which a second material may be injected or already placed to rigidfy the backing. This is somewhat of an attempted improvement over the Cronin device which uses a back porous layer such as a Dacron fabric. There are many other proposed suggestions, but they were also found to have disadvantages and flaws.
Thus, the devices heretofore proposed for overcoming the capsular contracture problem have not been found to be effective. It is also very important that the implant can be readily removed in its entirety from the human body in the event that an infection or undesirable reaction to the implant occurs or should total repositioning or total removal be desired for whatever reason.